I do it for nearly every trip. Yeah, the air somehow sneaks into some bags, but over all, I find it to be very organized....shirts, shorts, undies, swim suits...each have their own bags. Then, when it is time to pack up, I pack all the dirty clothes in separate bags from the clean ones. I don't think it makes a really big difference as far as how wrinkles the clothes get.
Plus, it seems we always get picked to get our checked luggage searched by TSA. We seem to get those little white notes in our bags frequently! It makes that process seem a little less intrusive because your stuff isn't all rearranged in your bag.